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Cycle Skates

I once read that technology never dies.  There are people today that still make flint knives and start fires by friction.  Furthermore, these skills have been passed down generation to generation.  To prove the hypothesis, the authors got an old Sears Catalog from the 1890s and picked out two pages of stuff they had never heard of.  They found all of them still available for purchase somewhere. Why then, can I not find the Cycle Skates in this 1923 video? They were apparently invented in 1870. ( I cannot find the patent info as they seem to be from France. I know in 2004 someone "re-invented" them as Chariot Skates.   Anyway, I would like to learn how to make my own 1870 / 1923 style cycle skates.    Anyone out there who can help?

Topic by justjimAZ    |  last reply

deep cycle batteries

Can we and how do we convert a normal lead acid battery into a deep cycle battery?

Topic by sankyc    |  last reply

fridge cycle logger

Hello all, I'd like to know how efficient my fridge is. To do this, I need to have a record of the on/off cycling that the fridge does: I need to know how frequently it cycles and how long it stays on for. Does anyone know if this gizmo exists? (in the UK) If not, how would I go about making one? Thanks, mm

Topic by marquee.moon    |  last reply

Cycling Desktop Backgrounds

I would like to be able to have an automatically cycling desktop background, like the option on Mac OS X. I'm running Windows XP. Are there any utilities or something available to do this? No, I don't want to create a GIF file of the different wallpapers, that would be enormous.

Topic by CameronSS    |  last reply


I want to construct a motor drive to run a cycle . i have arduino and hbridge with but i require a circuit diagram to connect and control it?.i wat to know the working , connecting and controlling conceots of it

Question by Aniesh T M    |  last reply

how do i anodize aluminum?

Thinking of anodizing some aluminum parts im making. Does it matter what kind of aluminum? I want a durable finish, resistant to corroding.

Question by klunder_teach    |  last reply

Where can I find strong ring magnets?

I want to make a magnetic levitated suspension. I am not sure it will work as I expected. But I need em' ...... Somebody please tell me where I can find em' I don't wanna spend so much for those mags neither do I want to damage costly things to take those mags outta them.... I thought of using electro magnetism....but i am still learning more about it and that procedure is damn expensive Please help

Question by SravanamE    |  last reply

how to make magnetic and fluid resistance based exercise cycle?

Make a stationary exercise cycle with fine control on resistance to rotation

Question by anil.gadgil    |  last reply

Video, Awesome

Check Out my sweet Video.;=user&fmt;=6

Topic by vanpaun    |  last reply

bicycle mods

Saw bicycle cart mod,interesting do i put two wheels on the front of my bike?

Topic by mr.a.rice    |  last reply

Self charging an electric bike?

Hi all, I am always amazed at the ingenuity here and after many years of being fascinated I would like to ask my first question.  I'm thinking of getting or converting/building an electric cycle.  I've been told by local dealers that none except the very expensive have a recharge facility for sat when you go downhill or are freewheeling,  That seems a waste to me so I am thinking ... why not buy a used wheel with a hub motor and fit it at the front wheel and that raises the following questions in my mind ... Can hub motors be used in reverse as generators?   Would the output be speed (rpm) dependent and if so then if said cycle has say a 36 volt system would it only charge the battery if the 'generator' is producing 36v or close to? If so would it be better to find perhaps a 24v hub motor to use as a generator and charge the battery via a variable input, 36v output step-up? I appreciate it will be less than 100% efficient when both using electric at the motor and charging at the 'generator' but would anyone have any idea how inefficient?  I'm fit enough to cycle on the flat but would appreciate help on the hills!! I assume I will need a diode or similar ... does anyone know where I can find a suitable circuit diagram Lots of questions I know ... sorry. David

Question by HRobinson    |  last reply

What is the duty cycle of a welder? Answered

Is a 6% duty cycle good? Bad? Terrible? Worth blowing up?

Question by bowmaster    |  last reply

know of any small scale Rankine cycle engines that are classroom safe for a presentation?

Have a school presentation on a thermodynamic process and would like to present a Rankine Cycle but i havent been able to find one that i can build and run within a classroom just looking for a design or directions, even a video that i can use to build one

Question by SLC Student    |  last reply

Tron™ Light Cycle is for sell

I was just checking out Hammacher Schlemmer and I saw this. I can't believe the technology we have today. If anyone has $55,000 and is willing to spend it on anything, this is for you.

Topic by Dr. Pepper    |  last reply

I would like to know what motor should i use to run an electric cycle of a total load of about 50kgs? ?

It Is a solar powered vehicle. I would like to know the exact specifications of the motor which i can use it to run a cycle with a net load of 50kgs.

Question by pramodh kiranv    |  last reply

Automatic Potentiometer

Hi!  i need and automatic potentiometer it has to works max 5v i thouhgt about that and i can make it manually but it's to big and to weird  i want to ask you a form to make  it whit electronic components or a component ho can makes it i want to make a motor acelerates and desacelerates whith a soft curve and if its posible put the time of the cycle (example 40 seconds acelerat.... and .. desaceler...."cycle" or similar) Thanks Sorry for my bad english! Thanks! 

Topic by labalavermella    |  last reply

Timing system for 2 actuators

Hello all! I have 2x 12v actuators with 2 wires. I need to have both of them (at the same time) extend all the way and stay for 30 minutes and then retract completely for 30 minutes and cycle like this. What would be the simplest way for me to go about this? Cheers!

Topic by sandman420    |  last reply

Roland Big Boy ball trailer hitch?

I have one of the above trailers, the ball hitch should be secured to the cycle saddle clamp, however I am unable to re sucure the clamp tight enough to stop the saddle rotating and the saddle dropping down. I have seen a clamp which secures to the actual seat post and the ball hitch is secured to that, i am unable to locate such a clamp, I am sure someone will know or can help me find this item. I am having to use my trailer as a hand cart at present for going to the allotment each day. Please help if you can. Thank you Joanna

Question    |  last reply

50% duty cycle circuit

Hello i want to make 50% duty cycle circuit frequency is no problem : any frequency thanks

Topic by aymanok    |  last reply

Cycling activity, need help?

Next week, I will have a cycling activity, and I want to buy cycling shorts for my girl friend. Has any one tried It seems very cheap, but I am afraid of the bad quality.

Question by Hughes Jessica  

what is the cheapest way to make this?

What is the cheapest way to make a bicycle kart? see me and my mom are very poor "kinda" the money is tight here and i would like to make something cool like this but heres what i have to make one this is ALL i have i dont have anything else meaning this is all the parts and tools i have 1 ten speed mountain bike,1 weed eater "working",2 planks of wood "the legenth of my arm,1 pair of screwdrivers.gasoline "for the engine to run",1 spare bicycle tire,1 spare and rusty bicycle chain,wire plyers,1 hammer,i only have 10 dollars and no im not allowed to get a soldering iron/gun so if theres anything that you know of on how to make this please let me know.

Question by wizard744    |  last reply

Cycling Power Meter Details? Answered

Hello, I was wondering if someone could tell me what the specific electronic components of a typical cycling power meter are and how they work together?  The picture is of one by Power Tap that is located in the rear wheel hub.  I'd like to try to build something similar.  All I know is that it uses strain gauges.  I have zero electronics experience but I'm hoping to learn by working the problem backwards. Thanks in advance.

Question by Starbuckaneer    |  last reply

Cat Genie Faster Cycling?

Thank you for all your helpful information on Cat Genie.  I used your rotation arm instructions as soon as I got my Cat Genie 2 years ago.  They were simple and easy to follow I am also resetting my cartridges and saving tons of money. I am wondering if you could help with these two additional issues for Cat Genie 1) Inexpensive Cat Genie granules subsitute 2) Speeding up or making the cleaning cycle faster, reducing the time it takes for each cleaning cycle to complete. Thank you! Dave Stern Las Vegas, NV 702-416-4700

Question by desmisc    |  last reply

Up-cycle an electric blanket? Answered

Our non-woven electric blanket has become unreliable and has been retired.    Is there anything useful I can do with the cords or blanket itself?  It's a lot of bulk to put in the trash.  The wires in the blanket make it undesirable as a regular blanket or quilt lining. 

Question by mole1    |  last reply

deep cycle battery pack

Does anybody know what parts I'd need to make a 12v rechargeable battery pack for an upcoming road trip? I also need to know where I can find deep cycle sealed lead acid batteries for this project. I waited long enough to make a lithium ion pack, but now I changed my mind on the battery type to get 12v, and now I have no idea of what protections and electronic components I need for it. I'l post more info on available casing later, but I'll tell you now that it's like a small blue lego briefcase from when I was little. It's about the size of a texbook and I'd like to be able to put it in a small backpack to carry around school sometimes for my windows tablet. Update: I am available to buy any particular case, but wiring in a case can sometimes look bad, so I'd like it to store all wires internally and have a friendly look. Appearance was part of why I switched my plan from li-ion 18650s to lead acid. A block with printed volt and amp information looks better than a group of oddly sized cells. Also, no clocks.

Topic by leaf26    |  last reply

4 wheeled Quad-Cycle!

Has anybody made or thought about making an Instructable to make a 4 wheeled bike-like a car? I've seen them on the Internet for $3-4000. Thought it would be interesting because of higher gas prices.

Topic by potofgold    |  last reply

Global Warming

Okay I'm gonna open the global warming can o'worms. what does everyone think about that stuff? Cycle of the earth? Change in atmosphere? what is it? BS or the current greatest problem facing society?

Topic by wingman246    |  last reply

What is the motorcycle of your dreams? Price is no object.

If money was no object, what motorcycle(s) would you want to own? For me it would have to be a Vincent Rapide, or a Brough Superior. Also, I'd like to own some historic bikes, like ones that belonged to : Pancho Villa, Evel Knievel, Lawrence of Arabia, Elvis, Bob Dylan, Steve McQueen, or maybe Peter Fonda's Captain America.

Topic by skunkbait  

would putting a lead acid battery in a backpack damage it?

Im trying to find a relatively inexpensive way to run my laptop off of something that will fit in my backpack and will be something that i can carry. so far i found out that i need a deep cycle or marine battery for my inverter, and an enclosure to make sure i dont get sulfuric acid everywhere, but all of the research ive found were about home backup systems which are stationary. would putting a lead acid battery in a backpack and carrying it around damage it or make it leak? i also found a lot of lithium ion batteries on amazon around 700 to 1600 mah for $.50 - $1... the sellers that sell them for that much have good ratings, is there something wrong with these, or did i hit a goldmine? example:;=electronics&qid;=1273381311&sr;=1-20   if lead acid doesn't work (or the lithium ion), would 10 nimh d batteries work?

Question by the judge    |  last reply

Wheelchair Wheels

I'm a wheelchair user and I would like to change the side wheels and rims with a bike  geared wheel and push handles.   I need someone, brighter than me, to  work out how to combine the crankshaft and back wheel into one unit? If this could be done, I would extend the pedal shaft to become handles which I could push with my arms. Don't know if that is clear.. I've tried to add an image here, but Instuctables just not uploading anything!!! If you have any idea about the wheel idea, I would be grateful to hear? Many thanks Richard

Topic by DickyMac    |  last reply

Wind Powered Quad-Cart

I haven't seen anything this on here so I thought I'd step up. Engineers (or anyone who fancies themselves A DIYer) I found a few days back I little some very interesting Wind Powered Rides...six-or-seven-ways-wind-powers-vehicles OK so we know it CAN be done, but can it be done by a DIYer? OK here's my concept, Design and shape are optional but basic components are such: Take a pair of multi-speed Bicycles, their gearing will be the basic propulsion for this vehicle. Take one of the "bikes" and hook up a prop where the pedals "where" and set the wheel output to be higher then the prop speed, this should take care of the foreward movement once going. Now for the initial starting power (Bike 2), this can either be by petal, or by electric (solar/battery- up to you) But the basis for this whole thing is simple energy transfer, if the moving air over the prop causes the drive wheels to go, and by having them geared higher, the vehicle SHOULD move faster the faster you go ..Right? Can I get some math to back this up? it sounds like it would work.

Topic by Green_Primus    |  last reply

Peeponics doggy urine nutrient cycle system

Hi, I have a dog at home who uses a litter tray. It's basically a large plastic water run off tray with some AstroTurf. Currently, I have a pump that draws off liquids and deposits them into an empty soda bottle, which I flush down the toilet. But I was wondering if there is an easy way to convert the urine into nitrates which I could use in an aquaponics, or peeponics, system? Possibly using an attractive under water garden in a 25 gallon fish tank?

Topic by jmlidea    |  last reply

Powering 12v LEDs from 12v Deep Cycle Battery

Hey all, I'm trying to power some 3528 LED strands to hang from a shade structure I have outside. I picked up a 115 Ah 12v deep cycle marine battery, but I just wanted to make sure I could wire them directly to a distribution block without blowing anything up. The strands draw 6A of current so I was going to find the closest fuse to that value (10A?) to prevent any chance of overpowering the control boxes. Does this seem correct? Image shows roughly what I'm trying to do (black boxes around red wire are fuses, 1-3 are the LED control modules) Greatly appreciate any help!

Topic by synaptech    |  last reply

Where can i find a British Standard Cycle Die (9.35mm diameter, 26TPI) in the UK

Im after a British Standard Cycle Die (9.35mm diameter, 26TPI) to thread a steel stub axel so it will fit inside a bike hub like a spindle (with cones from an old spindle) if anyone knows where i can find one of these please get in touch! :D PS i live in the UK

Question by ooda55    |  last reply

Bicycle Trailer

Hi everyone I am going to start buildin a cycle (bike) trailer but is there a law what says it can't be bigger then.......? Please? Thank you  :-)  From Kris in England 

Topic by prison.whittaker    |  last reply

555 pwm AND frequency controllable? Answered

Hello, I've been breaking my head on this for a while now, and still couldn't find a correct solution for this. I want to be able to adjust the duty cycle (pulse width) with one potentiometer, and the frequency with another potentiometer, using a 555 timer. Adjusting the frequency shouldn't change the duty cycle! (which is the problem in All of the circuits I find online). This is an example of a circuit I find online, many of the circuits look just like this one (see picture) Now, the problem is that when you increase the resistance of the potentiometer for adjusting the frequency, that makes sure you can never get 0% or 100% duty cycle anymore! or not even close to that. It's because increasing that resistance, also decreases the 'discharging current' of the capacitor, so it will also increase the discharging time when that's not wanted. Without R2 it works perfectly, from 0% to 100% duty-cycle; but with the frequency potentiometer it all gets messed up. It's a little difficult to explain, I'll try it with another example :) To get 0% duty-cycle (or something close to that, like 10%), you'll need to make sure the path for Discharging the capacitor goes near 0Ohm. Increasing the potentiometer for the frequency makes that impossible because it's in series with the capacitor's charging and discharging circuit. So that would also increase the discharging time while I don't want that. When the resistance of the frequency potentiometer increases, the duty-cycle gets variable between just something like 45% and 55% (example) so that's not good. Is there any way do do this? :/ Thanks in advance, Elecotrials

Question by DELETED_Electorials    |  last reply

Amphibious bike design?

So I have an idea for an amphibious bike design and I have a very low budget, but im not sure if this basic design will even work

Question by masterbuilder    |  last reply

Are there small car-like motors out there?

I've been wanting to teach myself more about mechanics, and I want to work on a rebuild project. There are problems though: my workshop is small, I don't have a shop-crane, and there's not a lot of money to put into it. I was wondering If there are any motors that are just like that of a car's that are small, cheap, and readily available. I've taken apart a few two- and four- stroke engines, nothing more than a lawnmower. I want to self-educate myself more. Thanks.

Question by DIY Emilio    |  last reply

What would make a good cushion for a bike mounted video camera to minimize the vibration?

By cushion I mean like a gel bag or something. See this video to give you an idea of what I'm talking about. It appears that this clip was shot by the mounted camera which can be seen, but it actually was shot by holding the camera on a monopod in one hand as I rode. The mounted footage was way to jittery. The mount that is there on the crossbar needs to be cushioned somehow to at least make it as good as what you see, but not some big Steadycam contraption. The obvious answer is a good POV cam but the good HD ones are serious money. I appreciate any head scratching on this one.

Question by dayjack119    |  last reply

Cyclist attacks again...

Uh this is annoying after last year when there were attacks on cyclists made by motorists I've been thinking it better not happen again this year, well my fears turn out to be well founded, just as our bike month kicks off so does the war on cyclists...Coming down the hill towards work, going well over the posted speed limit of 30mph a boy racer in a vauxhall corsa boxed me in and tried to run me in to parked cars, i managed to get in front of him and out from behind the parked cars, he then went on the wrong side of the road and overtook me, only to try and brake check me, I was absolutely incensed he was looking me right in the eye through the rear view mirror, He got away at the junction at the bottom of the hill because the light was green and he was going straight on, I was going to take out his wingmirror but nay he didn't stop, next time I see the car I'll get his liscence plate numbers, then report his car as stolen... because he'd get off scott free for attacking me like that, despite having endangered my life and broken the speed limit by a lot more than I did...

Topic by killerjackalope    |  last reply

Can I use fuel prepared for a 2 cycle engine in a 4 cycle engine? Answered

I wonder if it is safe to use the fuel prepared with the 2 cycle engine oil in a 4 cycle engine lawnmower.

Question by blkhawk    |  last reply

My Cycle Two Stroke Engine

Hello everyone, I wonder if any one can help me? I have fitted a two stroke engine kit to a cycle of mine, the thing was running perfect for 220 odd miles then starting stopping and would start again after a few minutes of pedalling. I have changed the petrol mixture and this has seemed to alter things slightly, now it will go but will not rev and only goes to a certain speed then starts kangarooing. When I engage the clutch it will not ideal it just conks out. Could there be something wrong with the accelerator perhaps? Thanks a very frustrated Paul

Topic by Paulygriff    |  last reply

need help with 2 cycle motor

So i am having some severe issues with a motorbike i am building. i have an old 2 cycle mccholluch pro-scaper weed eater. i took it apart, cleaned it, put it back together with a brand new plug and it ran nicely. Now, a few days later, it wont even start, not even a putter. i have tried everything, even a hefty shot of ether in the carb, but still nothing. i know i am getting volts to the plug b/c i checked with my meter, but im not sure if im getting spark. it is a brand new plug. any help would be greatly appreciated. thanks.

Topic by the mechanical engineer    |  last reply

60 cycle hum in a power supply

I recently scavenged a 5 VDC phone charger to use as a power supply for my small FM transmitter. I have the transmitter plugged into the computer so I can listen to my favorite internet radio station on the stereo in the living room, rather than only in the office. The whole thing works really well, except that during quiet songs or in between songs, I can hear that 60 cycle hum coming from the radio. Does anybody have any suggestions (cheap, free, or re-purposed parts are a plus) on how to minimize this? I don't want to spend money on this, and simple is my favorite adjective with electronics projects. Can I put a capacitor across the + and - wires to smooth out the power? If so, what size would be good? Thanks for your help! ~PC

Topic by Poppa Chubby    |  last reply

I wish to make electricity with my cycle (can be made stationary) - can't afford to buy ANYTHING, am that poor. Help.?

I intend to make my cycle a stationary one so that I might exercise at home. With that, I hope to create electricity as well (someday sell electricity too hopefully :D ) Of course I do not have much - and I need help to create the same without buying a thing preferably. Help please. Also suggest how I could store the same, just in case I successfully make some.

Question by Iyer2711    |  last reply

Railbiking. Anyone built one?

I heard an interview today with author William Least Heat-Moon.  In his latest book, he meets a man who has built an outrigger bicycle he calls a "Railcycle", which he uses to ride on disused railroad tracks all over the world. Curious, I did some searching, and found a number of places on the web where people are talking about this, but they all seem outdated. Bentley Railbikes Railbike Tours Homebuilt Railbike Has anyone else heard of this practice?  Do you know of anyone currently making and riding such contraptions?  Do you have one of your own?

Topic by yoyology    |  last reply

Idea for a non-ideal Carnot cycle based engine.

Initial Stirling engine conceptFor some time I was contemplating an idea for a Stirling engine that would work quite differently than the other designs that I came across. Whole internal volume of an engine may be viewed as a closed-loop pipe, trombone-like slide mechanism allows this pipe to change its length. Electrical fan replaces displacer and pumps working fluid throughout the engine constantly and in one direction. Some portion of the pipe is replaced with branching structure that consist of two heat exchangers (hot and cold) and regenerator. On both ends of this structure special valves are located that connect one of the structure’s parts to the main pipe, so that whole engine forms one closed-loop. While this happens, both of the unused parts are completely bypassed.This design should have many advantages. Working gas is in constant motion and little energy is wasted on accelerating it. Gas may pass many times through heat exchangers, allowing for much better approximation of isothermal processes. Disconnecting unused heat exchangers from the rest of the engine should minimize volume of dead spaces.There are some drawbacks to. Slide mechanism allows only very small changes of total volume (compression ratio is low), and that limits engine’s ability to operate with higher temperature differences. Piston, which is part of the slide mechanism, and especially valves, are heavy and this makes them unsuited for high speed operation, making the whole engine bulky. I also except that an area of all surfaces that are sliding against each other and produce friction would be higher than in traditional Stirlings.Problems with Stirling cycleIdeal Stirling cycle (Fig. 4) consist of two isothermal processes (constant temperature) during which work is performed, and two isochoric processes (constant volume, no work performed). Isochoric processes function is only to change temperature of the working gas, and this takes a lot of energy to do so (especially if gas with high heat capacity is used). Regular Stirling engines try to minimize this inefficiency with regenerator. But when I tried to analyze this process mathematically, I noticed that even regenerator with very high heat capacity cannot store more than half the energy needed to perform next isochoric process (see lower left part of the spreadsheets for more details).Fig. 5 represents heat pump (or refrigerator) working in a modified Stirling cycle. Isochoric processes represent transfers of heat to and from the regenerator. Rest of the temperature change is performed by polytropic processes, during which heat flows to or from the heat exchangers and also work is performed. I chose to represent heat pump, instead of a engine because engine working with this modified cycle wold require isochoric processes to be performed midstroke (or transfers of heat to regenerator would have to be performed during polytropic processes, when working gas changes its temperature also due to work being performed).Note that I am using word polytropic to indicate processes where gas changes its energy both due to heat transfers and work performed. When special cases of polytropic process are mentioned (isothermal, adiabatic, isochoric) I use their specific names.Solving those problems with Carnot cycleLegendary Carnot cycle consist of two isothermal processes (just like Stirling cycle), but changes of temperature are accomplished by the adiabatic processes (no heat transfers with the surroundings), instead of isochoric ones. This has huge advantage, because when energy is added to the working gas during adiabatic compression, all of it can be later recovered during adiabatic expansion.Design I previously mentioned can easily be adapted to work as a Carnot engine. Only change that is necessary, is replacement of regenerator with the empty pipe (ADIABATIC PIPE in Fig. 2). When valves connect this empty pipe to the rest of the engine, there is no heat transfer between working fluid and thermal reservoirs. Any changes of engine volume modify temperature and pressure in a approximately adiabatic fashion. To model what happens with the engine I used slightly modified Carnot cycle (Fig.3). Just before adiabatic process end, short polytropic process begins. It is done so that loses associated with valves connecting both adiabatic pipe and heat exchanger to the main part of the engine for a short period of time can be better simulated. Heat pump working in this cycle is shown in Fig. 6.Design detailsEngine uses special valves, which external shape resemble truncated cone. Smaller base of this cone faces main part of the engine, larger one heat exchangers. Inside there is a pipe, with one opening right in the center of smaller base. The other opening is located off-center on the larger base, so it can connect to the one of the heat exchangers or adiabatic pipe (which are situated just like chambers of a revolver’s cylinder in respect to each other). As this engine engine will most likely operate under low RPMs, flywheel will have to be connected through a transmission with very high gear ratio. The flywheel will have to be quite bulky as well. This poses another challenge, as the pressure inside engine’s tubing will be higher than atmospheric, and at least space around the other side of the “piston” will have to be pressurized as well. If only the immediate surroundings will be pressurized, and gears, flywheel, electric motor/generator will be outside of the container, then very inefficient seal will have to be employed. If everything will be located inside the pressurized container, then fast moving parts will be working against dense gas. Pressure in this area ideally should have such a value, so that on every piston stroke energy is both added to the flywheel and extracted from it as to make energy storage requirements more manageable. This requirements may also be further reduced by employing some other energy storage form. And of course exchange of heat between main part of the engine and this pressurized section must be taken into consideration.Then, there is problem of heat exchangers. They can be either large diameter pipes with fins, or smaller diameter ones that are densely packed (this seems to be must popular configuration in Stirling engines). As heat transfer with the outside of the engine takes around half of the piston stroke, it might be a good idea to employ two pumps of heat transfer fluid per each of the two heat exhangers. One would work constantly to transfer heat from some large heat reservoir, the other would transfer heat to the working fluid only when it is necessary. Some another heat exchanger would have to be placed between those two circuits.And there is also a question of the piston. Basic trombone-like version could be replaced by the something similar to the design drawn in Fig. 7, where two parallel tubes, connected by U-shaped piston, are replaced by the coaxial pipes with volute on the outer section that allows connection another parallel pipe. Piston itself has then small tubular part attached which allows working fluid to pass from outer section to the inner section. This design has only one high pressure seal, is possibly lighter, but fan that pumps working fluid will probably need to be more powerful. Problem of sideways motion of the piston must also be analyzed, and it can be either resolved with piston skirts or the crosshead. Interesting aspect of this problem is that while most frictional forces in the engine are mostly independent of the engine speed, forces associated with this sideways motion of the piston increase with engine rotational speed.Another possible improvement would be making adiabatic pipe shorter than the heat exchangers, which would reduce volume of dead spaces.Engine parametersIn case of a engine that uses helium as a working fluid, has minimum volume of 46.7 liters, maximum volume of 70 liters, operates at temperatures of -5°C and 37°C with the speed of 15 RPM you can expect that it will produce 1138W of power at 8.13% efficiency.In the case of heat pump that operates at the same parameters you can expect that it will require 2300W of power and achieve COP 4.95You can find calculations, diagrams and the detailed descriptions inside (it is unfortunate that Instructables do not support uploading .zip files and other file formats any more, and I have to use another website just to upload few spreadsheets).Possible applicationsI started thinking about this concept when considering applications of thermal energy storage. In more northern latitudes largest factor in domestic energy consumption is heating. So, at least in my opinion, any movement toward replacing fossil fuels with renewables should focus on this largest contributing factor. And this actually is quite fine because storing 1 kWh in a tank filled with water, rocks/concrete or simply in the ground is much cheaper than storing it inside lithium-ion batteries. And general idea behind this low temperature engine, was that some part of this large amount of energy stored to be later used to heat buildings, could be converted into electricity.It should also be able to work in reverse as a heat pump or refrigerator.

Topic by rarinn  

PET. (plastic bottles) Are there any other methods for colouring PET. (Please NOT Sharpies) Answered

I want to find out any other ways of colouring plastic besides sharpies. I want to use heat for shaping and I find sharpies don't provide a consistant covering for my needs. Please list any you know of for me to try. Looking foreward for your replies.

Question by craftyv    |  last reply

To all Bike riders/cyclists/commuters: What do you ride?

I ride a 2000 MGX DxR [yes, the crappy, chinese, walmart version] to work every day, road commuting. I also ride it off-road, singletrack, streams, washboards, you-name-it-I've-ridden-it, with no issues. thus far, I have put around 19,000 miles on it, all told. totally original [otherthan tubes, tires, chain, cassette, brakes, etc] parts, still weighs 38 pounds. Anybody else ride something as cheap and inappropriate as commuter? What do you ride every day? any bikes you'd LOVE to have? Any funny bike stories? Cheers,    B.E. 'Brick' Montgomery 

Topic by Hazzard2theworld911    |  last reply

How to control DC motor off and on cycles.

I need to control a radio control boat,  i want to cycle the motor on and off to extend the life of the batteries 6 - 12 v 40A my feed would be a normal radio control speed controller Thanks Ian 

Question by ian.collins.771    |  last reply